62970 research outputs found
Sort by
Coupled Surface Plasmon-Phonon Polaritonic Metasurfaces for an Active Control of Long-Wave Infrared Light
No full textTwo-dimensional arrays of subwavelength resonant nanostructures, called optical metasurfaces, control the wavefront of light in free space and optical waveguides by introducing spatially varying optical responses. Metallic optical antennas are often used as metasurface units, relying on surface plasmon polaritons. However, controlling long-wave infrared light from the mid-infrared to THz is challenging due to strong scattering at metallic nanostructures, which leads to considerable optical power loss. This dissertation seeks new types of metasurfaces capable of controlling long-wave infrared light by utilizing low-loss and highly efficient light-matter coupling in polar dielectric nanostructures. First, I discuss my early research participation in the development of passive and active resonant nanocavities designed for propagating mid-infrared (100 meV) coupled surface plasmon-phonon polaritons (SPP-SPhPs) utilizing silicon (Si) and vanadium dioxide (VO2) on a silicon carbide (SiC) substrate.
In my dissertation work, we develop deep far-infrared (33 – 37 meV) passive and active optical resonant nanocavity structures based on hybrid coupled SPP-SPhPs modes, utilizing silicon dioxide (SiO2) and VO2 on a gallium arsenide (GaAs) substrate. To address the challenges of far infrared microscopy caused by the lack of suitable optics, we have developed our own reflectance measurement setup and carefully designed and fabricated large patterns (micron feature size with mm-wide device) to enhance light-matter coupling. We observed a strong Fabry-Pérot cavity resonance of the coupled SPP-SPhPs on GaAs, which shifts to longer wavelengths as the cavity width of the devices increases. Additionally, we can thermally dope charge carriers in GaAs, enabling active control of the resonance shift. These far-infrared metasurfaces demonstrate significant potential for developing tunable optoelectronic devices in the underexplored long-wave infrared spectrum
Ready! Set! Go? Using a One Health Lens and Approach to Explore How Rhetoric and Reality Intersect
No full textOne Health is frequently positioned as a solution to complex health challenges at the intersection of humans, animals, and the environment. It is widely celebrated for its collaborative ideals and systems-thinking approach. However, much of the One Health literature presents a polished narrative that may obscure the practical and structural barriers that complicate its implementation. This dissertation critically examines the dissonance between the rhetoric of One Health and its reality in practice, expanding beyond its traditional domains of zoonoses and antimicrobial resistance. The research presented draws on quantitative methods and application of nontraditional theoretical underpinnings to demonstrate the power of transdisciplinarity.
By applying a One Health lens, the research reveals that the dominant narratives often underplay issues of power, disciplinary silos, and uneven capacities. Findings are framed through the One Health Joint Plan of Action and the One Health Theory of Change, offering three pathways for change – policy and advocacy, sectoral integration, and shared knowledge – as tools for bridging the gap between what One Health promises and what it delivers. In doing so, the studies contribute to ongoing conversations about the future of One Health, emphasizing the need for more reflexive and contextually grounded approaches
Participatory Design and Gaming: The User Experience Research and Development of a Playable Public Service Announcement
No full textDeceptive patterns are a form of manipulative design that exploits psychological principles to advance commercial objectives. Despite growing concern, legislative efforts to regulate these practices have been slow to take effect. In response, both scholars and industry professionals have sought to increase public awareness of the matter. However, research suggests that awareness alone is insufficient for mitigating the influence of deceptive patterns. This dissertation explores the development of an interactive intervention intended not only to increase awareness of deceptive patterns but also to educate users about the underlying mechanisms of manipulation through gameplay. Drawing from Inoculation Theory and developed using user-centered design methodologies, the intervention aims to cultivate both recognition and critical evaluation of persuasive design techniques.
This project was developed using a four-stage iterative design framework. This included a collaborative design workshop informed by Scandinavian participatory design principles and a semi-structured playtesting session modeled on game design quality assurance methods. Qualitative data collected throughout these stages was analyzed using iterative coding rooted in grounded theory. This analysis yielded eight key insights for game designers using user-centered methods and six generalized insights for UX practitioners. This work synthesizes academic theory and industry practice to demonstrate how interactive media can be used to critically engage users with contemporary issues through the means of play. The findings presented suggest that metaphorical game mechanics aided in users’ abilities to recognize manipulate design in practice, and that user-centered design methods fostered user reflection on the subject matter. These insights suggest that interactive interventions can go beyond awareness building and create lasting inoculative resistance using unorthodox and user-centered means of design
The effect of sex and gender-based stereotype threat on knee sensorimotor control in active individuals during different type of tasks
No full textKnee injury risk remains disproportionately high among females/women (f/w), potentially due to both sex-specific factors like
sensorimotor control (SMC) deficits and gender-specific sociocultural influences such as stereotype threat (ST). This study
investigated the effects of sex and ST on knee SMC during maximal effort knee strength, single-leg step-down, and drop vertical
jump (DVJ) tasks in 35 physically active adults (17 f/w, 18 males/men [m/m]), aged 18 - 30 years. Pre- and post-ST testing was
conducted, with 13 2(sex) x 2(condition) mixed ANOVAs (Hochberg-corrected) analyzing the effect of sex and gender-based ST on
knee flexor and extensor peak torque, and rate of torque development (RTD) during a maximal effort knee strength task, and 30
knee kinematics and kinetics during two full-body coordination tasks (single-leg step down and single-leg drop vertical jump [DVJ]).
The m/m demonstrated significantly greater knee extensor peak torque (p<.001), while sex effects for RTD and flexor torque were
inconclusive.The ST exposure significantly reduced knee flexor RTD (p=.030) in both f/w and m/m. During the step-down task, f/w
displayed significantly greater frontal plane knee abduction (p=.013), and there were inconclusive sex effects on frontal plane knee
angles during single-leg DVJ. Secondary Spearman correlations (n=52) revealed that in f/w, higher exercise identity scores were
significantly associated with pre-ST knee extensor RTD (rho=0.64, p=.005). These findings highlight sex-specific knee SMC
differences and suggest that gender-based ST may impair maximal knee flexor strength performance
Technology-Integrated Professional Development to Improve Teacher Self-Efficacy
No full textThe purpose of this insider action research is to identify the effect of professional development integrating high-yield instructional strategies with technology tools on teacher self-efficacy and the potential effectiveness of the Texas Teacher Evaluation and Support System (T-TESS) Dimensions 1.1 and 1.4 for evaluating teacher levels of technology integration. This insider action research employs a convergent parallel mixed-methods approach, involving surveys, semi-structured interviews, and observer-as-participant classroom observations. Utilizing Tschannen-Moran and Hoy’s Teacher Self-Efficacy Survey, the effects of professional development on teacher self-efficacy will be measured, compared, and studied. The findings of this study indicate that all teacher participants experienced an increase in self-efficacy with instructional technology and strategies, resulting in a 21.50% increase in overall teacher self-efficacy after participating in integrated professional development. Additionally, this study found that administrators can utilize the T-TESS evaluation system’s dimensions 1.1 and 1.4 to evaluate and teachers to self-evaluate the level of technology integration in a classroom, using look-fors to assist administrators and teachers in applying the T-TESS rubrics to evaluate levels of technology integration
Mechanisms Mediating Protective Metabolic Effects of Beef Ammoniation in Diet-Induced Obese Male and Female Mice
No full textThe prevalence of obesity has been increasing for decades, significantly increasing the risk of comorbidities including type 2 diabetes, cardiovascular disease, and several types of cancer. The growing obesity epidemic has been accompanied by shifts in dietary patterns, characterized by higher consumption of saturated fats, sodium, and fatty meats such as beef, collectively known as the western diet. The regular consumption of such foods in a western diet can contribute to a condition known as diet-induced low-grade metabolic acidosis. This low-grade metabolic acidosis can exacerbate chronic low-grade inflammation and is linked to the development of obesity and other comorbidities. It was previously reported that mice consuming pH-enhanced beef diet exhibited metabolic improvements compared to mice fed non-pH-enhanced beef, however, the underlying mechanisms of these effects remain unclear. This dissertation examines the effects of diets containing ammoniated beef in both low fat and high fat diets on inflammation, white adipose tissue (WAT) function, gut microbiota composition, and gut integrity in both male and female C57BL/6J (B6) mice with diet-induced obesity.
Male and female B6 mice were randomized into 4 diets that differ in pH enhancement and fat content: Low fat beef (LFB), pH-enhanced (via ammoniation) low fat beef (LFBN), high fat beef (HFB), and pH-enhanced high fat beef (HFBN). Dietary intervention lasted 12-13 weeks, followed by terminal collection of tissue and fecal samples. Our lab previously reported that ammoniation attenuated HF diet induced metabolic impairments [2]. In this study, we measured markers of inflammation, glucose homeostasis, and fatty acid metabolism in gonadal WAT, as well as assessment of changes in gut microbiota composition via 16S sequencing, and markers of gut integrity in intestines to examine potential mechanisms underlying the improvements observed.
Analyses revealed that HF diet significantly increased weight gain and fat mass in male mice, with females showed no significant changes. Ammoniation significantly reduced fat pad mass in males, with no effect in females. Histological analysis revealed similar results, demonstrating reduced adipocyte area and increased adipocyte number in males, while females exhibited no such changes. Three-way ANOVA analyses confirmed sex differences to be apparent across these results. mRNA and protein analyses (by qPCR and western blot) in WAT, revealed that most significant changes were driven by fat content (LF vs HF), rather than ammoniation. Microbiome analyses by16S sequencing demonstrated that HF diets significantly altered the composition of gut microbiota, with limited differences being attributable to ammoniation. However, assessment of gut integrity markers revealed that ammoniation significantly increased the expression of gut integrity genes in the intestine of females, with no differences across the male groups.
Our study is among the first to investigate the metabolic and microbiota impacts of altering the pH of individual food components, in this case via ammoniation. Consumption of diets containing ammoniated beef exhibited beneficial effects on fat mass, glucose clearance, and gut integrity markers in diet-induced obese mice. Overall, these findings demonstrate that ammoniation, as a food processing technique, may provide some metabolic health benefits, highlighting the importance for collaboration between the fields of food and nutrition scientists to address the current epidemic of metabolic diseases from production and processing to consumption. Future studies are warranted to further determine underlying mechanisms by which ammoniation modulates metabolic health
Application to Encryption and Encoding Utilizing Biochemical Assays
No full textBioaffinity interactions can provide a new approach to producing cipher keys in cryptographic methods. Bioaffinity interactions represent highly individualized outputs based on metabolism that can be applied to numerous concepts. By utilizing data from enzymatic and immunoassays, this research shows that cipher keys can be applied to a symmetrical encryption system. This methodology combines cryptographic and steganography concepts with the encryption standards, American Encryption Standard (AES) and American Standard Code for Information Interchange (ASCII), to encrypt and decrypt messages. While using these encryption standards provides robust information security, the binary number system and a PIN pad system were also utilized to improve the current encryption methods. Specific parameters of these assays produce a unique cipher key from a signal output to reduce the risk of repeat keys that could allow for interception by an external party. The addition of bioaffinity-based assays to the symmetrical encryption system provides an extra security measure. Two different encryption systems are employed in this research: AES, coupled with a binary number system, and ASCII, coupled with a PIN pad system. Cipher keys are derived from enzymatic assays for both encryption systems. The AES system utilizes an immunoassay to protect the encrypted message in binary form, while the ASCII system employs character encoding to store the encrypted information. The ASCII system will also apply a PIN pad system, where certain parameters must be used to obtain the correct signal for encryption and decryption. Only the “correct” PIN will produce the correct cipher key to decrypt the message by the intended receiver. These concepts can enhance current cryptographic methods by introducing additional security measures while utilizing a novel biochemical approach to standard cipher algorithms, which generate cipher keys for encryption
Dual Credit and Educational DisAdvantage for Low-Income Students: A First Look at FAST-Eligible Students’ Postsecondary Outcomes
No full textDual Credit (DC) programs help students make progress toward earning college credentials while they are still in high school. DC courses are affordable and help students save on college tuition or develop skills through career and technical courses that prepare them for good-paying jobs. It is an important strategy for Texas to continue building a skilled workforce for the 21st-century knowledge economy. However, students with low-income family backgrounds face major challenges in accessing DC. Low-income students are both more likely to encounter financial barriers to pay for DC and less likely to meet DC eligibility criteria
Design and Development of Fission/Fusion Rocket Propulsion System
No full textThe pursuit of advanced nuclear propulsion is essential for enabling efficient and sustainable deep-space exploration. Among the most promising concepts, the Fission Fragment Rocket Engine (FFRE) leverages the direct expulsion of fission fragments to achieve unprecedented levels of specific impulse, significantly surpassing conventional chemical rockets. However, realizing a practical FFRE requires overcoming fundamental challenges in charged particle confinement, fuel containment, and material interactions in extreme space environments. This dissertation presents an interdisciplinary study integrating experimental, computational, and theoretical approaches to address these key challenges and will enable and advance FFRE development.
A central focus of this work is solving two primary challenges: in containing fissile fuel, which must be at the sub-micron scale to enable fission fragment escape, and in confining fission fragments along a thrust axis for effective propulsion. We propose an innovative design that combines high magnetic fields to define the thrust axis by confining the fission fragments, with low-density aerogel matrices for fuel containment. This approach employs a strong magnetic field to guide and sustain fission fragment trajectories while embedding micron-sized fissile material within aerogels to maintain subcriticality while allowing fragments to escape for thrust generation. This dual-containment system enhances the feasibility of FFREs by ensuring stable fuel configurations while maximizing fragment exhaust efficiency.
To validate the confinement approach, we conducted an extensive study of charged particle dynamics in high magnetic fields, using alpha particles as surrogates for fission fragments due to their comparable charge-to-mass ratio and velocity. An innovative alpha particle detection system was developed within a 3-Tesla MRI superconducting magnet, providing a unique experimental platform to analyze particle motion and confinement. Using Americium-241 (²⁴¹Am) and Thorium-232 (²³²Th) sources in an aluminum vacuum chamber, we performed simulations and experiments to measure alpha particle flux, transport behavior, and periodic refocusing effects governed by the transverse cyclotron motion. These findings offer crucial insights into sustaining fission fragment trajectories within a magnetic nozzle for propulsion.
Beyond confinement, we investigated aerogel-based fissile fuel containment. A significant design challenge in FFREs is ensuring fission fragments escape the fuel layer without excessive attenuation, which would degrade propulsion efficiency and increase the waste heat deposited in the fuel. Using Monte Carlo N-Particle (MCNP) simulations and CR-39 nuclear track detectors, we analyzed particle attenuation within aerogel matrices of varying densities and compositions. Our study identified a critical areal density threshold (~10²⁰ atoms/cm²) beyond which attenuation becomes substantial, and below which the aerogel is essentially transparent to the alpha particles. These findings inform the selection of optimal aerogels that allow efficient fragment escape while maintaining fuel integrity and stability.
In addition to fission-based propulsion, we explore a fusion-assisted hybrid FFRE concept that leverages neutron-induced tritium generation to enhance propulsion efficiency. Specifically, we examine triton-induced fusion reactions using neutron interactions in lithium deuteride (LiOD). Exposing LiOD to a Cf-252 neutron source triggers the 6Li(n,t)4He reaction, producing tritons, which subsequently undergo D-T fusion to generate high-energy 14.1 MeV neutrons, and t+6Li fission that produce two more less energetic neutrons. Using CR-39 detectors, we identified neutron interactions via the n+¹²C → 3α reaction, confirming very high neutron energies that come only from DT fusion events. This process not only supports the development of hybrid fission-fusion propulsion, where fusion reactions provide additional thrust and energy, but also contributes to broader applications in clean energy generation. The ability to initiate fusion reactions using neutron-induced triton production presents an opportunity to harness compact fusion sources for future clean energy without long-lived radioactive waste.
By integrating charged particle confinement, aerogel fuel containment studies, and hybrid fission-fusion cycle, this dissertation establishes a comprehensive framework for advancing fission/fusion propulsion technologies. The experimental methodologies, computational models, and theoretical insights developed here lay the foundation for future FFRE prototypes while advancing knowledge in plasma physics, nuclear materials, and space propulsion. More broadly, this work contributes to fundamental research in plasma physics, nuclear materials, and space propulsion, with potential applications extending to fusion energy systems, space-based reactors, and high-energy plasma confinement. As humanity prepares for deep-space exploration, the insights gained from this research bring us closer to realizing high-performance nuclear propulsion systems capable of enabling interplanetary human travel, and robotic exploration beyond our Solar System
Making our Monsters: Forced Disabling in American and Canadian Horror Films
No full textMy dissertation challenges the common perception that horror cinema merely vilifies disability, strictly by perpetuating harmful stereotypes of disabled individuals as monstrous. I contend that while horror films have consistently used characters’ physical, intellectual, and psychological disabilities to evoke fear and revulsion, revisiting the genre through the lens of disability studies reveals that portrayals of disability are not universally exploitative, but rather point to more complex historical intersections. The dissertation introduces and defines the concept of “forced disabling,” a phenomenon where individuals are deliberately disabled (mentally, emotionally, or physically) for the benefit of others, as distinct from disabilities that arise naturally or through accidents. The dissertation examines how the genre uses disability as a form of Othering and draws on trauma studies, Indigenous studies, and race and gender studies to uncover how this trope intersects with historical systems of oppression and targeted racial discrimination. These include, in particular, the legacies of anti-Black racism through practices such as exploitative medical experimentation, police brutality, and forced sterilization, as well as anti-Indigenous racism through tactics like cultural erasure, enforced dependency, and physical and psychological violence within settler-colonial frameworks. By comparing films directed by white male filmmakers with those by women and people of color, the study traces evolving trends in disability representation across time and cultures. Chapters include analyses of ways that concepts of race and gender inform the forced disabling of white protagonists in The Shining (Stanley Kubrick, 1980) and Misery (Rob Reiner, 1990) the ways female directors explore bodily autonomy through “body horror” in films such as American Mary (the Soska sisters, 2012) and Boxing Helena (Jennifer Lynch, 1993), and the way the historical institutions of slavery and Indigenous genocide manifest as forced disabling in the films of Black filmmakers including Jordan Peele’s Get Out (2017), and Indigenous filmmakers including Jeff Barnaby’s (Mi’kmaq) Rhymes for Young Ghouls (2013). My dissertation offers a comprehensive understanding of how forced disabling operates within horror and highlights its cultural significance and sheds light on how filmmakers from diverse backgrounds engage with themes of trauma and disability, all of which provides a more inclusive perspective within the genre. Ultimately, my research demonstrates that, rather than universally denigrating disability, horror uses it to reflect and critique deeply rooted societal injustices. Through a blend of disability studies, trauma theory, and intersectionality, my research reveals the multilayered ways in which horror uses disability to reflect and critique historical and societal injustices